Switch between 2 Insert Queries on Select option or Radio Button - php

Question

I want to run 2 different INSERT queries on the dropdown select option
If user selects option 1 the Insert Query for Table 1 runs.
When the user selects option 2 the other Insert query for Table 2 runs.
<?php
if(isset($_POST['submit_form']) && isset($_POST['listings'])) {
switch ($listings) {
case 'GradeA':
$stmt = "INSERT INTO Packing_listA (Country, Total_bales) VALUES ('$Country' , '$Total_bales')";
break;
case 'GradeB':
$sql = "INSERT INTO Packing_listB (Country, Total_bales) VALUES ('$Country' , '$Total_bales')";
break;
}
if ($mysqli->query($stmt) || $mysqli->query($sql) === TRUE) {
$last_id = $mysqli->insert_id;
$_SESSION['ct_id'] = $last_id;
echo "<p>New record created successfully. Last inserted ID is: '". $last_id."'</p>";
echo "<script>setTimeout('delayer()', 1000)</script>";
}
} ?>
And the HTML is
<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" method="post" class="form" role="form">
<select style="font-size:1.5em; height:45px;" class="form-control" name="listings" >
<option>Choose Color</option>
<option value="GradeA" <?php if($listings == "GradeA") print('selected="selected"'); ?>>GradeA</option>
<option value="GradeB" <?php if($listings == "GradeB") print('selected="selected"'); ?>>GradeB</option>
</select>
<div class="form-group">
<center>
<button style="height:45px; font-weight:bold;" name="submit_form" class="form-control btn btn-lg btn-info">
Next
</button>
</center>
</div>
</form>
But I am open to any other method Like Radio Buttons or If, Else condition or anything that works.
When the option 1 is selected only associated Query will run and vice versa.

Answer 1

First, I'll go for something like this :
if (isset($_POST['submit_form']) && isset($_POST['listings'])) {
$sql = "INSERT INTO "
."Packing_list".($_POST['listings'] == 'GradeA'? 'A' : 'B')
."(Country, Total_bales)"
."VALUES ('$Country' , '$Total_bales')";
if ($mysqli->query($sql)) {
$_SESSION['ct_id'] = $mysqli->insert_id;
echo "<p>New record created successfully. Last inserted ID is: '".$_SESSION['ct_id'].
"'</p>";
echo "<script>setTimeout('delayer()', 1000)</script>";
}
}
Second , I think you can make a better code (strange think in this one...)